Without having email addresses of your event attendees, you can:
1) Share the digital gift bag URL on your website. We suggest adding it to a thank you page after ticket purchase or simply part of your event description.
2) Create a poster or display sheet to place at registration tables or exits, thanking attendees and inviting them to claim their virtual gift bag at http://www.donationmatch.com/gift-bag
3) You may print copies of the 3-to-a-page downloadable certificate and add them to gift bags or hand them out with auction receipts.